I don't think that it can be done, even with a third party WebCam.
Maybe others know different.
I have just been to the MS Messenger site and note that MS does not support, or even mention, video from a Mac.
Go figure.
P
Hey, Is it at all possible to set up the standard cam installed with an imac with msn messenger? Or if not would anyone possibly know of any webcams compatible with os tiger?
New to macs.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic